// 页面添加水印效果
const setWatermark = (str: string) => {
    const id = '1.23452384164.123412416'
    if (document.getElementById(id) !== null)
        document.body.removeChild(<HTMLElement>document.getElementById(id))
    const can = document.createElement('canvas')
    can.width = 200
    can.height = 130
    const cans = <CanvasRenderingContext2D>can.getContext('2d')
    cans.rotate((-20 * Math.PI) / 180)
    cans.font = '12px Vedana'
    cans.fillStyle = 'rgba(200, 200, 200, 0.30)'
    cans.textBaseline = 'middle'
    cans.fillText(str, can.width / 10, can.height / 2)
    const div = document.createElement('div')
    div.id = id
    div.style.pointerEvents = 'none'
    div.style.top = '0px'
    div.style.left = '0px'
    div.style.position = 'fixed'
    div.style.zIndex = '10000000'
    div.style.width = `${document.documentElement.clientWidth}px`
    div.style.height = `${document.documentElement.clientHeight}px`
    div.style.background = `url(${can.toDataURL('image/png')}) left top repeat`
    document.body.appendChild(div)
    return id
}

/**
 * 页面添加水印效果
 * @method set 设置水印
 * @method del 删除水印
 */
const watermark = {
    // 设置水印
    set: (str: string) => {
        let id = setWatermark(str)
        if (document.getElementById(id) === null) id = setWatermark(str)
    },
    // 删除水印
    del: () => {
        const id = '1.23452384164.123412416'
        if (document.getElementById(id) !== null)
            document.body.removeChild(<HTMLElement>document.getElementById(id))
    },
}

// 导出方法
export default watermark
